The use of ceiling boards, both panels and tiles, is well known. Such boards can be made of any suitable material. Those containing glass fibers and having a surface coating find wide usage. Frequently, such boards are supported on ceiling grid or gridwork. Often the boards so supported drop slightly below the gridwork. This is because the edge is in the form of a flange or other protrusion which is retained on the gridwork and the substantially vertical edge portion between the surface of the flange which rests on the grid and the major exposed surface of the ceiling panel or tile (know as the reveal) is exposed. Such an edge is known as a tegular edge.
In order to provide a finished appearance to such edges, it has been customary to apply an edge coating or paint. Such paint is sprayed into the corner of the flange formed by the flange surface which contacts the grid (know as the perch) and the reveal. Some of the paint overlaps the major exposed surface of the ceiling panel (or front face) and the distal end portion of the flange. However, because such paint has not been durable, the boards have been susceptible to edge damage, such as denting, gouging, and scratching, due to handling and installation in the ceiling grid. This causes unsightly appearing tegular edges.
The ceiling board edge coatings of this invention increase durability and deter such difficulties. Further, the edge coatings of this invention permit application of an edge coating which does not result in picture framing or drying problems. Picture framing is the change in gloss level around the edge of the major exposed surface of the ceiling board due to an overlap in the edge coating and the paint coating which is applied to the major exposed surface. If the edge coating requires additional drying time or higher temperatures, the ceiling boards may warp.
As stated previously, it is well known to paint the edges of ceiling boards to improve appearance. For example, see Gleason et al. U.S. Pat. No. 4,559,377. However, composition of Gleason et al. is not the same as the present invention and such patent does not address the issue of durability. Therefore, the need for more durable tegular ceiling board edges continues to exist.
Caldwell et al. U.S. patent application Ser. No. 5,386, filed Jan. 9, 1998, for High Light Reflectance and Durable Ceiling Board Coating, which patent application is commonly owned, describes a durable paint for ceiling boards. However, the composition of such paint is different than the present invention. Further, there is no teaching of improving the durability or strength of flanges on ceiling boards. The paint composition of Caldwell et al. is applied perpendicular to the front face and does not coat the ceiling board reveal.
Accordingly, it is an object of the present invention to provide a ceiling board with more durable edges.
It is a further object to provide such a ceiling board which does not adversely affect the appearance of the major exposed surface of the ceiling board.
A still further object is to provide such a ceiling board which does not require additional oven drying.